The objectives of this proposal are (1) to train the candidate (Dr. Grossman) in the skills necessary for him to become an independent investigator in the field of ocular motor research (2) to study, in a series of laboratory projects, the multi-dimensional behavior of the ocular motor system. During the Phase 1 training period, the candidate will take courses in control systems, matrix and tensor analysis, differential equations, statistics, computer science, and instumentation. In addition, projects listed below will be started to train the candidate in experimental methods and hypothesis testing. The research techniques will involve measurement of eye and head movements in 3 planes using the magnetic search coil approach and interpretation of data using control systems analysis. These projects will be completed during phase II. The first project is a study of the horizontal, vertical and torsional components of oblique saccades in normal subjects. The latency, velocity, accuracy and duration of each component of the movement will be measured. Results will be interpreted with reference to a quantitative hypothesis (mathematical model) of oblique saccades. The second project aims at determining the effects of discrete brainstem (pons, midbrain), hemispheral (parietal, frontal), or cerebellar lesions upon the normal control of oblique saccades. We will refer to our model of the normal control of oblique saccades to determine which parameters are most likely to be affected by specific disorders. The third project will study the frequency, velocity and amplitude of rotational head perturbations that occur during locomotion. The fourth project will examine the effectiveness of the vestibulo- ocular reflex in holding gaze steady during locomotion. These projects will (1) provide new information on the normal control of oblique saccades; (2) probe disorders of ocular motor control by analyzing specific features of oblique saccades; and (3) establish what range of stimuli should be employed to test the vestibulo-ocular reflex in patients who complain of vestibular symptoms during locomotion.